The present invention relates to a differential temperature sensor device used to detect and visually display surface temperatures on a body within a predetermined range. The device is particularly useful in the early detection of cancerous tumors and disease in the human breast.
There are many known devices and methods for the detection of cancerous breast tumors and breast disease. Procedures for the detection of breast tumors and breast disease presently include physical examination, mammography, xerography, and thermography.
For a historical discussion of the various methods of detecting breast cancer and disease see the article by Gershen-Cohen et al entitled "Modalities In Breast Cancer Detection Xerography", in Cancer (December, 1969), pp. 1226-1230; see also "Advances In Thermography and Mammography", by Gershen-Cohen et al, Annals New York Academy of Sciences (1964), pp. 283-300; and "Relative Densiometric Analysis of Thermograms", by Brueschke et al., Annals New York Academy of Sciences (1964), pp. 82-89.
In the 1950's, it was discovered that the surface temperature of skin in the area of a malignant tumor exhibits a higher temperature than that expected where no disease is present. Thus, by measuring skin surface temperatures, it became possible to screen for the existence of abnormal body activity such as cancerous tumor growth. This knowledge was eventually applied to the detection of malignant breast tumors and breast disease. Consequently, much effort has been expended in exploring different approaches to measuring skin temperature in the breast region. The goals in this area have been to provide a non-invasive, inexpensive, self-contained, comfortable, reliable device for performing such screening, while at the same time giving the patient both a sense of privacy and control over when and how the screening process is performed.
Many different devices and methods have been directed towards breast cancer and breast disease detection through temperature measurement. For example, U.S. Pat. No. 4,428,382 to Walsall et al. discloses a probe responsive to thermal radiation which is passed over skin to measure its temperature and identify the presence of abnormal tissue. A thermoresponsive screen used in conjunction with a photographic system is described by U.S. Pat. No. 4,524,779 to Brown, Jr. In U.S. Pat. No. 4,055,166 to Simpson et al., a brassiere is disclosed in which transistorized temperature sensors are disposed in order to provide skin temperature measurements for the purpose of locating cancerous growths. A similar device based on thermistors used in conjunction with a neural network is disclosed in the U.S. patent to Deban et al. (No. 5,301,681). However, each of these types of approaches typically failed to meet one or more of the goals described above.
With the development of liquid crystals and methods of forming temperature responsive chemical substrates, contact thermography became a practical method of breast cancer and breast disease screening. Devices employing contact thermography were developed which could sense and display temperature changes through indicators which changed colors, either permanently or temporarily, when placed in direct physical contact with a skin surface reflecting a temperature at or near the point of contact. This technology enabled a contemporaneous temperature measurement of both of a woman's breasts to be made and compared since dissimilar temperatures in the same regions of opposing breasts could indicate the presence of malignancy or other abnormality. An anomalous temperature comparison reading would at least indicate the need to seek more detailed examination of the physical regions in question.
The accuracy of such devices is contingent upon sustained, uniform contact for an adequate time period between the breast and thermographic sensors. As women's breasts are a variety of different shapes and sizes, and women wear a variety of different styles and sizes of brassieres, the passive placement of sensors in general contact with the breast, such as in a brassiere, cannot insure sufficient, uniform, sustained contact between breast and sensor to yield a reliable temperature profile. A portion of the breast may not come into contact with a sensor, or may move away from the sensor before the examination time passes. The body of prior art comprises many breast temperature sensor devices. However, none of them adequately solved the problems of inaccuracy, discomfort and difficulty of use of breast temperature sensor devices.
U.S. Pat. No. 3,847,139 to Flam discloses a substrate of body-conforming material carrying a temperature responsive coating viewable against the substrate background for displaying a temperature indicative pattern when the structure is worn over the breasts. However, the Flam device was a cumbersome one, designed to be worn between the neck and waist of a woman and required an intricate fastener.
Flam U.S. Pat. No. 3,661,142 discloses a temperature-sensing patch which is attached on one side to a flexible backing web and on the other side to a plurality of discrete temperature-sensitive indicators. Each indicator comprises a layer of encapsulated cholesteric liquid crystals, which have the property of changing color with changes in temperature. However, this device provided a limited area of measurement. U.S. Pat. No. 3,830,224 to Vanzetti et al. was directed to the placement of temperature sensors in a brassiere. However, the area of measurement provided by this device also was limited. Further, the device required a predetermined brassiere shape which resulted either in certain areas of the breast not contacting a desired liquid crystal or the breasts themselves being deformed into an unnatural shape by the brassiere thereby damaging the reliability of the resulting temperature reading.
Uniformly close contact between skin and sensors was provided by Meyers et al. (U.S. Pat. No. Re. 30,466) in which temperature responsive film containing temperature sensitive liquid crystals was wrapped across the breast area and the air between the breasts and the film was mechanically evacuated. But this invention required specialized, expensive extra equipment for its implementation. U.S. Pat. No. 4,524,778 to Brown Jr. et al. disclosed an approach in which hot areas indicated by a thermographic scanning band overlaying the breast area were traced by hand onto an overlying web and the highest temperature at each site of unusual activity indicated by the thermogram was separately measured in situ by means of a hand-held liquid crystal activated thermometer so a record of temperature readings over time can be obtained. This device required multiple measurement steps and depended on readings from single temperature indicators spaced out over a relatively large area.
Another temperature-responsive device for detecting the presence of breast cancer is described by James et al in U.S. Pat. No. 3,960,138. This device is retained in thermal contact with thermistors in each cup of a brassiere, which are connected to create a differential temperature integrator circuit, whereby any difference in mean temperatures between the two breasts may be monitored over a period of time.
A series of patents to Sagi (U.S. Pat. Nos. 4,190,058 and Re. 32,000; U.S. Pat. No. 4,624,264 and U.S. Pat. No. 4,651,749) generally described disc-shaped cancer detection patches for aid in early detection of breast cancer based on thermography. The patches comprise radially arranged rows of temperature responsive indicators deposited on a plurality of pie-shaped, heat-conductive web segments made of aluminum foil. The patches are placed into the breast-receiving cups of a brassiere, in contact with the breasts, then visually examined for temperature differentials to determine possible abnormality of breast tissue.
The backing of the Sagi patents, webbing composed of solid metallic foil, especially when mounted on a support surface, does not always conform well to complex three-dimensional shapes such as human breasts. In addition, although the diagnostic device of Sagi provides the ability to cover a much broader area of breast surface than the prior art, it is not self-contained and must be manufactured in a multiplicity of sizes to accommodate different breast shapes and sizes. Then, if the brassiere into which the segments are inserted does not itself fit perfectly, uniform skin contact with the diagnostic device is still not achieved. Moreover, in order to compensate for differences in brassiere design, insertion of the segments into the brassiere could result in overlapping segments causing the indicators of some segments to become hidden and, therefore, useless.
One way to insure sustained contact between breast and sensor is to attach a sensor directly to the breast itself, preferably using an adhesive. However, application of adhesive directly to the sensor can interfere with the transmission of heat to the sensor, resulting in inaccurate readings. Further, large surface-area contact between breast and adhesive also can irritate breast skin and can make removal of the sensor from delicate breast skin difficult.